回複：回複：回複：回複：回複：Answer to question 3

a=li,b=huang,c=lin,ad=a was died......
P(a^b^c)=P(a^bd^c)=.7*.5=.35---1)P(a^cd)=.3, 2)P(ad^c)=.7


P(a^b^cd)=1-.35=.65---1)P(a^b)=.35,2)P(a^bd)=.3, 3)P(ad^b)=.35---1)P(a^b)=.65,2)P(a^bd)=.3,3)P(ad^b)---.....
So,P(a^bd^cd)=.35*.3+.65*(.3/(1-.35))=.405
P(ad^b^cd)=.65*(.35/(1-.35))=.35
P(ad^bd^c)=.35*.7=.245 or 1-.405-.35=.245.
The intuition told us,let c kill b,a shot air,but c exists is dangerous more.
You are very smart, We can change some prob. Let first one shot air,..became best policy.The question will be more intereting. The last names would be changed to Li,Wei and Fu ...better.